I need a new car!!!! but....?

I'm thinking about getting either honda civic coupe, accord coupe, toyota corolla, or scion tc. When is the best time to get a new car??? ive looked around yahoo and it said that it's best to get it in august. Is it better to get a car august or at the end of the year? When do the dealers have better deals on the cars? I want a 2009 model rather than a 2010 if dey have better deals!!!